Fountain coater



United States Patent 3,521,602 FOUNTAIN COATER James T. Coghill, Fulton, N.Y., assignor to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Filed Dec. 18, 1967, Ser. No. 691,297 Int. Cl. B05c 3/02, 3/18 U.S. Cl. 118410 12 Claims ABSTRACT OF THE DISCLOSURE A fountain coater bar with a removable nose bar member defining an off-running coating land tapered toward the backing roll and being formed of relatively short dimension as compared to the width and depth of the coating trough, and an on-running land which forms a tapered wedge with the web providing a region of lowering pressure for the removal of entrained gasses within the coating material and for the separation of air entrained with the web prior to entering the trough.

RELATED APPLICATION This invention comprises an improvement in fountain coaters of the type disclosed and claimed in the copending US. application of Phelps et al., S.N. 408,163, filed Nov. 2, 1964, and assigned to the same assignee as this application notw Pat. No. 3,418,970.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The present invention is directed to an improved fountain bar member for fountain coaters. The fountain bar of the present invention is particularly adapted for coating of webs of paper and the like with liquid coating materials at high web speeds, such as 3,000 feet per minute and above.

An on-running or upstream land forms a converging nip with the web, in the direction of web movement. With respect to the coating trough, the upstream land diverges away from the web and thus provides an expansion region permitting the expansion and release of entrapped, and sometimes partially dissolved, air and gasses within the coating material itself, thus releasing such gases prior to coating. Further, a downwardly diverging portion is formed adjacent the upstream land which additionally assists in separating air carried frictionally along the surface of the web before the same is drawn into the coating trough.

A downstream off-running land is formed with a converging nip toward the web, and with a transverse distance which forms a relatively small part of the corresponding Width of the trough. Additionally, such downstream land is preferably formed on a removable nose bar to permit easy replacement in the event of wear.

A longitudinal coating trough is formed in the fountain bar which is both relatively deep and relatively wide as compared to the on-running and off-running land surfaces, and is bottom fed by a plurality of inlet passageways so that there is a substantially uniform coating pressure longitudinally of the bar for the even application of coating material by an off-running land. The trough is thus formed with a volume which greatly exceeds that defined between the on-running and off-running lands and the adjacent surfaces of the web.

The relatively narrow coating land formed on the offrunning side of the trough or on the removable nose bar is formed with a width which is related to pumping pressure and web speeds to provide relatively high unit pressure, due to the hydraulic wedge formed between the coating surface and the web, for intimate application of the coating material onto the surface of the web. By making the width of the off-running land relatively narrow, the total forces on the fountain bar are reduced while the unit pressure is maintained or increased.

In the preferred embodiment, the removable nose bar piece is self-holding in place in a groove and against the off-running side wall of the trough by reason of the coating pressures which are applied to the fountain bar.

Further advantages and objects of the present invention will be evident from the detailed description of the preferred embodiment and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical section through an improved fountain bar on a fountain support assembly, showing the manner in which the assembly is supported on a transverse support frame member of the coater;

FIG. 2 is a further section through the fountain bar assembly showing the manner in which the fountain bar is joined to the coating supply tube;

FIG. 3 is an enlarged vertical section through the fountain bar showing fragment of the rubber covered backing roll and the web supported thereon; and

FIG. 4 is a fragmentary perspective view of the fountain bar and its associated supply tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT The improved fountain bar of this invention is shown at 10 in FIGS. 1 and 2 as forming part of a fountain assembly which is indicated generally at '12. The general coater structure and the assembly 12 are constructed as described in greater detail in the above-identified Phelps et al. patent. The assembly 12 mounts on a fountain support beam 13, which may be of generally rectangular section, and which extends substantially transversely the width of the coater. The assembly 12 and the supported bar 10 are mounted on the coater for limited floating movement generally toward and away from a rubber covered backing roll 15 (FIG. 3) by means of support arms, not shown, received on the respective coater stands, in coating a web 16 of paper or the like guided by the roll 15.

The assembly 12 includes a transversely extending, generally cylindrical coating supply tube 18, positioned in underlying relation to the improved fountain bar 10, forming the means for supplying liquid coating material to the bar 10. For this purpose, the tube 18 may be opened at its opposite ends for connection with suitable pipe unions for the supply of liquid coating material therein.

The fountain bar 10 is secured in superimposed sealed relation to the tube 18 by means of a plurality of identical clamp assemblies 20 which are positioned in longitudinally spaced relation along the length of the tube 18. One of the clamp assemblies 20 is shown in elevation in FIG. 2 as including a pair of identical opposed clamp members 21 and 22. The upper ends 21 of the clamp members are received in the bar 10 in opposed relation within suitable longitudinal grooves 23 and 24 formed in the opposite exterior sides of the bar 10. The clamp members 22 and 21 are received in generally encircling relation to the tube 18 and have lower portions 25 which are held in abuting relation by a cross bolt 26 extending beneath the tube 19 between the clamp members 22 and 21. Each of the clamp members 22 and 21 is also formed with a pair of outwardly or transversely extending ears 27. Semi-circular collars 28 are received in encircling relation to the bottom of the tube 18, and are formed with outwardly extending tabs 29, 30 which are engaged by threaded bolts 32 received through the ears 27. When the bolts 32 are tightened the clamp members 22 and 21 draw the fountain bar 10 firmly against the upper surface of the tube 18 and retain these parts in rigidly assembled relation. Suitable elastomeric sealing strips 33 and 34 are positioned between the upper surface of the tube 18 and the lower fiat surface of the bar 10 to form a fluid-tight seal with the bar.

The fountain assembly includes hangers for supporting the tube 18 and fountain bar 10 on the support beam 13, and one of these assemblies is shown at in FIG. 1. A plurality of such hanger assemblies 40 are employed longitudinally of the fountain assembly 12 in alternating relation to the clamp assemblies 20 of FIG. 2. The assemblies 40 support the fountain bar 10 and tube 18 on the beam 13 for movement therewith, and further provide for vertical adjustment of the fountain bar 10.

The hanger assembly 40 includes a pair of rigid upright support members 42 and 43 which are welded in spaced apart relation to an upper surface of the beam 13, and which are fixedly spaced apart by, and welded to, an inverted U-shaped spacer '44. A pair of identical hanger brackets 45 and 46 have lower ends which are adjustably secured respectively to the upright supports 42 and 43 by bolt pairs 47. The bolts 47 pass through enlarged openings in the hanger brackets 45 and 46 and into threaded openings in the supports 42 and 43 and provide for limited vertical adjustment of such brackets.

The upper ends 48 of the hanger brackets 45 and 46 are turned inwardly toward each other and are also received within the fountain bar side grooves 23 and 24. Interfitting keys 50 and 51 are received respectively within suitable horizontally disposed key slots formed in the hanger brackets 45, 46 and in the vertical supports 42 and 43. The keys are provided with cooperating sloping interfitting tongues and grooves and are movable transversely one to the other within their respective key slots to effect fine vertical adjustment of the hanger brackets 45 and 46 with respect to the cross beam 13.

The improved fountain bar 10 of this invention is shown in greater detail in FIGS. 3 and 4 as having means defining a generally rectangular coating trough formed in the upper surface thereof and extending partially into the bar 10. The trough 60 is open at its top and has a vertical on-running side 61, a bottom 62, and an opposite side 63. The trough 60 may be formed with a depth which is equal to, or which somewhat exceeds, its width, as shown in FIG. 3.

Means for applying coating liquid into the interior of the trough includes a plurality of inlet or feed openings 64 which are formed with a width substantially equal to the effective width of the trough and which extend vertically from the bottom surface of the trough through the bottom of the bar 10, and are aligned with correspondingly aligned openings 64' in the tube 18. The spacing of the fountain bar inlets 64 is such as to supply liquid coating material to the fountain trough 60 in such quantity as to form a substantially uniform pressure of coating material transversely of the trough 60. As a specific example, the spacing of the openings 64 may be /2 inch or less up to 1%. inches or more, with inch spacings for openings of inch in diameter being typical.

The inlet side of the trough is terminated at a g nerally planar on-running land surface 65 which is preferably formed normal to the adjacent side wall 61 of the trough 60. The on-running land preferably has a transverse width which forms a small part of the corresponding width of the trough, and, as shown in FIG. 3, extends a distance approximately one-half that of the effective width of the trough.

Preferably, the fountain bar 10 is positioned in offset relation to the vertical centerline of the backing roll, as shown in FIG. 3, and in this position the on-running land 65 forms a converging nip with a tangent to the web at the opening of the trough 60.

The on-running land 65 is joined with a downwardly sloping surface potion 66 extending to the side wall 67 of the bar 10, forming a somewhat greaer angle with the incoming web than that formed by the land 65. The portion 66 may be inclined at approximately 15 of the land 65, as indicated at 68 in FIG. 3, and assists in the separation of entrained air prior to entering the trough 60. The surface 66 also aids in preventing injury to the roll 15 and bar 10 in the even of breakage of the web.

The fountain bar further includes means defining a downstream, off-running, or metering planar land 70 formed in spaced relation to the land 65. The land 70 is preferably formed along the upper surface of a generally rectangular removable nose bar 72, the inside surface of which defines the downstream wall of the trough 60.

The nose bar 72 has a lower edge which is recessed within a notch 74 formed longitudinally of the bar 10 along the bottom of the trough 60 and adjacent the downstream wall 63 of the trough. In this manner, the bar 72 is self-seating and self-holding in the recess 74 and against the downstream wall 63 by reason of the coating pressure and the forces applied to the exposed surfaces of the nose bar 72. For the purpose of assuring retention of the nose bar 72 in its seated position, a plurality of cap screws 76 may extend through suitable openings formed in the wall 63 and into aligned tapped and threaded openings formed in the nose bar 72. However, the ca screws 76 need not be depended upon to hold the nose bar in place as it will remain firmly seated in place during coating by reasons of the forces tending to seat the bar 72 into the slot 74 and against the surface of the wall 63.

The vertical height of the wall 63 is somewhat reduced as compared to that of the trough wall 61 so that the nose bar 72 extends a short distance above the wall 63 as indicated at 77. Thus, while the off-running metering land 70 is formed with essentially the same elevation or height as the on-running land 65, it is spaced somewhat above the adjacent surface of the bar itself.

The land 70 is preferably formed with a uniform taper as indicated generally at 80 in FIG. 3 so that while the sharp on-coming edge 82 of the land 70 is directly across from the corresponding edge of the land 65, the offrunning edge 84 is somewhat elevated toward the web 16. The taper thus defined by the angle 80' forms a converging nip with the web in the direction of web movement. In addition, it has been found that the greater wear on the nose bar occurs at the off-running edge 84 and by providing a slight taper, in the order of between 2 to 6, compensation for such wear may be built into the nose bar 72, thus extending the effective life of the nose bar while assuring optimum operation over a longer period of time.

The transverse width of the land 70 also forms a relatively small part of the corresponding width of the trough 60 and may, for example, be substantially the same as that of the on-running land '65. However, the spacing between the land 70 and the surface of the 'web to be coated, during coating, forms a converging nip both by reason of the offset position of the fountain bar upstream with respect to the center line of the roll and by reason of the taper at 80. Accordingly, this space is substantially less than the space defined between the land 65 and the Web 16 with the result that the land 65 forms a region of comparatively lower pressure. Since this region is expanding in a direction away from the trough 60, it assists in the removal of entrapped air and other gasses from the coating material by permitting the expansion of such gasses as a coating material overflows the on running surface 65 and the downwardly tapered surface 66. Further, these surfaces assist in removing entrained air which is frictionally carried by the web toward the trough and which would otherwise be carried into the trough.

The employment of a metering land 70 which is formed with a relatively narrow transverse width results in relatively high unit pressures with respect to the paper surface and may even result in some deformation of the rubber covering of the roll at the region of the nip with the result that there is infusion and good bonding of the liquid coating with the web surface even at high web speeds, with no overflow of coating material on the offrunning side of the fountain. Further, the use of such relatively narrow coating land results in lower overall forces being on the fountain bar as compared to bars where wider off-running lands are used, thus reducing the total forces IWhiCh tend to warp or bend the bar, and reducing the total forces necessary to retain the bar in desired coating relation to the web.

While the form of apparatus herein described constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise form of apparatus and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

21. In a fountain type web coater apparatus for applying liquid coating to a moving web of sheet material in which such coating is applied to a trough formed on a fountain bar for application to a :web of such material supported on a backing roll, the improvement in fountain construction, comprising a coating supply tube having an upper surface, a fountain bar mounted on said supply tube upper surface and having a plurality of longitudinally spaced passageways opening into said supply tube for receiving coating material therefrom, means in said bar defining a transversely extending coating trough which is generally rectangular in cross-section and open at the top and having an on-running side, an off-running side, and a bottom, with said passageways opening into said trough bottom, a longitudinal groove formed in said trough bottom adjacent said off-running side, a nose bar having a lower portion received in said trough groove and positioned adjacent the said olf-running side of said trough, and means on the upper surface of said nose bar defining a coating land extending a finite distance from said trough in the direction of web movement.

2. The apparatus of claim 1 in which the width of said coating land is less than the width of said trough.

3. The apparatus of claim 1 in which said coating land is planar and is formed with a taper defining a converging nip with said web.

4. Theapparatus of claim 1 further comprising means in said fountain bar defining an on-running land extending generally normally from said on-running trough side and forming an expansion region with the adjacent web surface for the removal of gas entrapped with said coating and for the removal of air entrapped with the exposed surface of said web prior to entering said trough.

5. The apparatus of claim 4 in which said on-running land and off-running land each have transverse widths which are less than the width of said trough and in which each of said lands are substantially equal to each other in width.

6. The apparatus of claim 4 in which said fountain bar is formed with a downwardly diverging entrance portion coterminous with said on-running land and extending therefrom to the adjacent side of said bar at an angle to said web greater than that defined by said on-running land and assisting in the removal of entrapped air and for preventing damage to said backing roll in the event of breakage of the web.

7. Fountain coater apparatus in which a liquid coating is applied to a transverse trough of an upwardly opening fountain for application to the moving web of sheet material supported on a backing roll, the improvement comprising a fountain bar supported transversely of the direction of web movement having means therein defining said transverse trough adjacent an exposed surface of the web, said fountain bar trough being defined by an inside wall on an on-running side, a spaced off running wall and a connecting bottom, a removable nose bar supported on said fountain bar in said trough adjacent said elf-running wall and having a portion extending above said fountain bar and terminating at an upper surface defining an offrunnin g land extending for a finite width in the direction of web movement, and means on said fountain bar defining an on-running land extending upstream of said trough and transversely opposite said off-running land.

8. The fountain coater apparatus of claim 7 in which said off-running land forms a converging nip with the web in the direction of web movement and which said width thereof is less than the longitudinal width of said trough between said lands.

'9. The apparatus of claim 8 in which said on-running land forms an expansion region with said web, diverging from the web in the direction contrary to web movement for assisting in the removal of gas trapped within the coating material and assisting in the removal of air entrained with the web.

10. The apparatus of claim 9 further comprising means on said bar defining an on-running tapered portion coterminous with said on-running land and tapered at an increased angle away from said web as compared to that of said on-running land.

11. The apparatus of claim 7 in which said off-running land is formed as a taper on the upper surface of said nose bar in the order of from 2 to 6 forming a converging nip with said web.

1 2. The apparatus of claim 7 in which said fountain bar includes means defining a longitudinally extending groove formed in the bottom of said trough adjacent said off-running wall and in which said nose bar has a bottom portion received in said groove while being positioned adjacent said off-running wall so as to be selfholding thereat with the application of coating forces thereto.

References Cited UNITED STATES PATENTS 2,349,256 5/ 1944 Evans 118-411 2,464,771 3/ 1949 Van Guelpen 118-4l0 X 3,301,214 l/l967 Coghill 11841O X FOREIGN PATENTS 698,518 11/1964 Canada.

JOHN P. McINTOSH, Primary Examiner US. Cl. X.R. 18413 

